leupold vx-r for ar-15?

I have a 20" AR-15 that I have been using for a while with just the iron sights (I prefer irons to red dots) Now I want to use it for more of a precision short/mid range rifle (0-500 yds) I was originally thinking 1-4 power but am now thinking maybe 3-9 would be better

Which do you guys think would be best on a 20" ar
Leupold VXR Patrol in 1.25-4 or 3-9?

If my ar was a carbine with a 16" or shorter barrel it wouldnt even be a choice for me, the 1.25-4 would be the clear choice
but for a rifle length AR which would you guys prefer?

The barrel length isn't as important as how it'll be used. I think the 3-9x is more versatile for most situations, but I have a 1-4 on my AR deer rifle because my longest shot would be ~150 yards but may be as close as 10.